Syd Barrett, one of the original members of Pink Floyd, has died - 40 years after he helped make the group one of rock's most popular and influential bands.

Syd Barrett (bottom) led the band in their early years

Pink Floyd took the world of music by storm when they developed their own very original brand of rock.

In their heyday, their music combined symphonic orchestral elements with a generous and ground-breaking use of electronic and "concrete" music - clocks, planes, and other real-life sounds - as well as sharp lyrics.

Pink Floyd were formed in 1965 by four Cambridge students - Syd Barrett, Roger Waters, Rick Wright and Nick Mason.

David Gilmour soon replaced Barrett, who started to suffer from mental health problems.

Some dedicated Floyd fans still believe the short-lived Barrett period to be the band's best.

SELECTED DISCOGRAPHY - ALBUMS

The Piper at the Gates of Dawn (1967)

Ummagumma (double - 1969)

Atom Heart Mother (1970)

Meddle (1971)

Dark Side of the Moon (1973)

Wish You Were Here (1975)

Animals (1977)

The Wall (double - 1979)

Others, on the other hand, particularly admire the experimental period of the late 1960s and early 1970s - which produced difficult and often brilliant works such as Ummagumma, Atom Heart Mother and Meddle.

But the band's real worldwide success came in 1973 with one of the decade's defining works, Dark Side of the Moon, where they successfully combined the experimentalism of their early days with hi-tech electronic music and more melodic tunes.

The album also represented the first explicit foray into left-wing politics, with the band denouncing what they saw as the alienation caused by modern capitalist society. It stayed in the US charts for a record 27 years.

Roger Waters' anti-establishment lyrics - prominent in Dark Side of the Moon - came even more to the fore with the band's following albums, Wish You Were Here, Animals and The Wall.

The band reformed - without Barrett - at Live 8 last summer

A track on the 1979 double concept album The Wall, Another Brick in the Wall Part 2, was the band's only number one single.

Its success owed much to its most original feature, a choir of North London schoolboys rebelling against their teachers.

But an acrimonious break-up and legal wrangling followed.

Pink Floyd's most successful line-up - Roger Waters, David Gilmour on guitar, Rick Wright on keyboards and Nick Mason on drums - did not play together after the days of The Wall.

But more than 20 years later, they got back together for one night at last summer's Live 8 concert in London, with that quartet embracing on stage once more.

Any hopes that it would lead to a permanent reunion remain unfulfilled, with the band releasing a statement in January claiming press stories about a comeback had misled fans.

Even if Gilmour and Waters fail to patch up their notorious long-running row, both continue to tour and record and keep the Pink Floyd legend alive.